FDA has concern on female 'Viagra'

Regulators raise doubt a day ahead of panel review

By

LauraGilcrest

WASHINGTON (CBS.MW) -- A day before Procter & Gamble's Intrinsa testosterone patch for women goes before an advisory panel, the U.S. Food and Drug Administration said Wednesday that it is concerned with the product's long-term safety.

Touted as "Viagra for women," P&G's transdermal testosterone patch would be the first therapy approved in the United States to treat low sexual desire disorder in women.

However, the FDA is asking its advisory panel on reproductive health drugs to look closely at the long-term safety of P&G's
PG, -0.40%
patch, which would be sold under the brand name Intrinsa if approved.

In panel briefing papers, FDA said that women who would use the patch -- those who became menopausal following surgery -- would also be on estrogen therapy. The agency said that a women's health study shows that estrogen increases the risk of stroke and that the testosterone patch might raise that risk even further in long-term users.

FDA also told the advisory panel that it remained skeptical whether P&G's sex dysfunction therapy offers a "clinically meaningful" improvement in its users' sex lives compared with a placebo. For example, the agency noted that women using the Intrinsa patch in P&G's studies reported having only one additional "sexual event" in a four-week period than those taking a placebo.

The advisory panel will meet Thursday in Gaithersburg, Md., to vote on whether to recommend approval of the first-of-its-kind therapy to treat low sex drive in women who become menopausal after their ovaries are removed surgically.

FDA is not bound to follow the advice of its panels, but does so in most cases.

Cincinnati-based P&G is developing Intrinsa with Corona, Calif.-based Watson Pharmaceuticals
WPI, -3.91%
which would manufacture the patch if it is approved.

About one in three women who have ovarian removal surgery report a decreased sex drive, and about one half of that group express concern about the condition, P&G said.

P&G estimates there will be 10 million surgically menopausal women in the United States by next year, with no therapy approved to treat the condition.

Other firms make estrogen transdermal patches such as Novartis'
NVS, -1.41%
Estraderm, or patches that deliver a combination of estrogen and testosterone.

Estrogen therapy treats menopausal symptoms like hot flashes, but does not help with sexual dysfunction in menopausal women, which can cause problems ranging from decreased sexual desire and sexual activity to a reduced sense of well-being.

The Intrinsa patch, which is applied twice a week, also has shown promise in enhancing sexual desire in women who have gone through natural menopause, which P&G estimated will affect 52 million U.S. women next year.

Plummer said the company would not likely file for the additional use before 2006.

If approved, Intrinsa could prove a major boon for Procter & Gamble, said market analyst Charles Georgas, who tracks P&G stock for Marquis Investment Research.

"You look to Viagra [sales] as a gauge," he said, adding that the total U.S. market for male impotence drugs is currently just under $2 billion and is expected to balloon to $2.5 billion by year's end.

The market for P&G's female sexual dysfunction therapy won't reach those proportions right away, Georgas cautioned, since the company is going after surgically menopausal women, a smaller market initially.

The FDA also is likely to approve the drug for use in naturally menopausal women. That could create new market possibilities, he said.

Georgas added that the market potential of P&G's groundbreaking therapy still has some unanswered questions, such as whether women will be as eager as their male counterparts to try a drug for sexual dysfunction.

The Intrinsa patch was tested in two 24-week, placebo-based clinical trials involving more than 1,000 surgically menopausal women aged 20 to 70 who were taking oral or transdermal estrogen.

According to P&G, Intrinsa was generally well-tolerated in the studies, with the most common side effects including application-site infection, upper respiratory infection and headaches.

The so-called androgenic reactions associated with testosterone therapies -- including unwanted facial hair, acne and a deepening of the voice -- were slightly higher in patients on Intrinsa vs. a placebo, P&G said. However, patients experiencing these relatively low-occurring side effects did not want to discontinue therapy.

Menopausal women have decreased levels of testosterone -- a hormone present in much lower levels in women than in men -- but which is necessary to sustain a healthy sex drive in women.

Premenopausal women who have undergone removal of the ovaries lose about half their normal testosterone level and about 80 percent of their estrogen, which can lead to decreased sexual desire.

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